Abstract: An erodable thermocouple is disclosed having two dissimilar metal conductors, connected or not connected as desired at the ends exposed to the temperature to be measured, the conductors being electrically insulated from each other along their lengths by glass sleeving, one being helically mounted on the other, the conductors being encased within a tubular insulating enclosure and surrounded by a kraft paper tube, the insulating enclosure and tube being swaged to reduce its outside diameter, and having a short metal tube at its outer end. The paper tube burns upon exposure to furnace temperatures providing a slip plane for the thermocouple.